Neutral scandium compounds having two univalent ligands or a bidentate, divalent ligand are known from Shapiro et al., Organometallics, vol. 9, pp. 867-869 (1990); Piers et al., J. Am. Chem. Soc., vol. 112, pp. 9406-9407 (1990); Shapiro et al., J. Am. Chem. Soc., vol. 116, pp. 4623-4640 (1994); Hajela et al., Organometallics, vol. 13, pp. 1147-1154 (1994); and U.S. Pat. No. 5,563,219 to Yasuda et al. Similar yttrium, lanthanum and cerium complexes are disclosed in Booij et al., Journal of Organometallic Chemistry, vol. 364, pp. 79-86 (1989) and Coughlin et al., J. Am. Chem. Soc., vol. 114, pp. 7606-7607 (1992). Polymerization with a metal scandium complex having a bidentate, divalent ligand using a non-ionizing cocatalyst is known from U.S. Pat. No. 5,464,906 to Patton et al.
Group-3-10 metallocyclic catalyst complexes are described in U.S. Pat. Nos. 5,312,881 and 5,455,317, both to Marks et al. U.S. Pat. No. 5,064,802 to Stevens et al.; and EP 0 765 888 A2. U.S. Pat. No. 5,763,556 to Shaffer et al. describes Group-3 olefin polymerization catalysts.
Polymerization of olefins with cationic Group-4 metal complexes is illustrated in WO 96/13529 and WO 97/42228. Boratabenzene complexes of Group-3-5 metals are disclosed in WO 97/23493.
Amidinato complexes of Group-3-6 metals are disclosed in U.S. Pat. No. 5,707,913 to Schlund et al. Group 4 bisamido catalysts are disclosed in U.S. Pat. No. 5,318,935 to Canich, et al., and related multidentate bisarylamido catalysts are disclosed by D. H. McConville, et al, Macromolecules 1996 29, 5241-5243.
S. Hajela, W. P. Schaefer, J. E. Bercaw, J. Organomet. Chem. vol. 532, pp. 45-53 (1997) describes the synthesis of Group-3 metal complexes (Me3-TACN)M(CH3)3 (M=Sc, Y) and reactions of the Sc species with activators ([PhNMe2H][B(C6F5)4] and B(C6F5)3) and subsequent polymerization of ethylene and oligomerization of 1-pentene (with unspecified catalyst activities).
L. W. M. Lee, W. E. Piers, M. R. Elsegood, W. Clegg, M. Parvez, Organometallics vol. 18, pp. 2947-2949 (1999) describes the synthesis of a scandium dibenzyl complex with a β-diketiminato ancillary ligand, and the generation, by reaction with the Lewis acid B(C6F5)3, of an ionic derivative with a contact ion-pair structure (unreactive towards alkenes).
M. A. H. Male. M. E. G. Skinner, P. J. Wilson, P. Mountford, M. Schröder, New J. Chem. vol. 24, pp. 575-577 (2000) reports the synthesis of a substituted 1,4,7-triazacyclononane ligand, iPr2-TACN-(CH3)3NH2 and a corresponding titanium TACN-imido complex [iPr2-TACN-(CH3)3N]TiCl2 (in which the ligand is dianionic).
Monoanionic substituted TACN ligands (with pendant phenolate or alcoholate functions) can be found e.g. in C. Flassbeck, K. Wieghardt, Z. Anorg. Allg. Chem. vol. 608, pp. 60-68 (1992), and in D. A. Robson, L. H. Lees, P. Mountford, M. Schröder, Chem. Commun. pp. 1269-1270 (2000).
The synthesis and structure of a lithium salt of a substituted TACN ligand with a pendant cyclopentadienyl anion is reported in B. Quian, L. M. Henling, J. C. Peters, Organometallics vol. 19, pp. 2805-2807.